Buffer overflow in Microsoft 365 Copilot
CVE-2026-50387
Stack-based buffer overflow in Windows GDI allows an authorized attacker to elevate privileges locally.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.003 (25.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 25th percentile — 25.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- Microsoft 365 Copilot
- Microsoft 365
- Microsoft Office 365 For Mac — versions 1.0.0
- Microsoft Office For Android — versions 16.0.1
- Microsoft Office Ltsc For Mac 2021 — versions 16.0.1
- Microsoft Office Ltsc For Mac 2024 — versions 16.0.0
- Microsoft Office 2021
- Microsoft Office 2024
- Microsoft Windows 10 1607
- Microsoft Windows 10 1809
Weakness classification (CWE)
References
- msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50387 (vendor-advisory, Patch, patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-50387?
- CVE-2026-50387 is a high-severity vulnerability in Microsoft 365 Copilot, classified under Stack-based Buffer Overflow. CVSS score: 7.8/10. Published 2026-07-14.
- How severe is CVE-2026-50387?
- High severity. CVSS v3 base score is 7.8 out of 10.